nuttx/net/utils/net_chksum.c
Alin Jerpelea 37d5c1b0d9 net: Author Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-02-20 00:38:18 -08:00

127 lines
3.7 KiB
C

/****************************************************************************
* net/utils/net_chksum.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET
#include "utils/utils.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: chksum
*
* Description:
* Calculate the raw change sum over the memory region described by
* data and len.
*
* Input Parameters:
* sum - Partial calculations carried over from a previous call to
* chksum(). This should be zero on the first time that check
* sum is called.
* data - Beginning of the data to include in the checksum.
* len - Length of the data to include in the checksum.
*
* Returned Value:
* The updated checksum value.
*
****************************************************************************/
#ifndef CONFIG_NET_ARCH_CHKSUM
uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
{
FAR const uint8_t *dataptr;
FAR const uint8_t *last_byte;
uint16_t t;
dataptr = data;
last_byte = data + len - 1;
while (dataptr < last_byte)
{
/* At least two more bytes */
t = ((uint16_t)dataptr[0] << 8) + dataptr[1];
sum += t;
if (sum < t)
{
sum++; /* carry */
}
dataptr += 2;
}
if (dataptr == last_byte)
{
t = (dataptr[0] << 8) + 0;
sum += t;
if (sum < t)
{
sum++; /* carry */
}
}
/* Return sum in host byte order. */
return sum;
}
#endif /* CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: net_chksum
*
* Description:
* Calculate the Internet checksum over a buffer.
*
* The Internet checksum is the one's complement of the one's complement
* sum of all 16-bit words in the buffer.
*
* See RFC1071.
*
* If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
* provided by architecture-specific logic.
*
* Input Parameters:
*
* buf - A pointer to the buffer over which the checksum is to be computed.
*
* len - The length of the buffer over which the checksum is to be
* computed.
*
* Returned Value:
* The Internet checksum of the buffer.
*
****************************************************************************/
#ifndef CONFIG_NET_ARCH_CHKSUM
uint16_t net_chksum(FAR uint16_t *data, uint16_t len)
{
return htons(chksum(0, (uint8_t *)data, len));
}
#endif /* CONFIG_NET_ARCH_CHKSUM */
#endif /* CONFIG_NET */